So my 06 Wakesetter VLX turns fine both direction at low speeds; however, at 20+ mph it's a real beast to turn it to the left. However, still turns with a finger to the right... Any thoughts on what might be causing this? The steering cable was just replaced two years ago by a shop in central IA.

I would unhook the cable and make sure the rudder moves smoothly. If it does replace the cable. Greasing the cable is more to keep out water to prevent corrosion. Once the cable gets stiff its usually a lost cause.